Staple for stapling machines



June 15, 1943. I OBSTFEQLD 2,321,847 7 STAPLE FOR STAPLING MACHINESFiled Jan. 2, 1941 n IIWHIIIIIHI j Him mum 1 INVENTOR 6 LOU OBSTFELDATTORNEYS M lllllllll' ig- Patented June 15, 1943 D STAPLE FOR STAPLINGMACHINE-S Lou Obsti'eld, Brooklyn, N. Y., assignor of one-'- half toAbraham Obstfeld, New York, N. Y.

Application January z, 1941, Serial No. 372,699

4 Claims.

This invention relates to the art of stapling, and more particularly toan improved staple for use with an improved stapling machine.

The primary object of my invention is to generally improve the art ofstapling, and more especially stapling machines and thin wire staplessuch as are usually cemented together tn form a stick.

A more specific object is to avoid jamming. of staples in the staplemagazine. Such a jam prevents further feed of staples by the staple feedspring, thus rendering the machine inoperative. In most machines themagazine is inaccessible except at one end forloading, and it istherefore a very diflicult matter to free a jammed magazine. Afterconsiderable study of this problem, I have come to the conclusion thatthese staple jams are caused by rotation of a free staple about its topor bridge until the legs point toward the legs of next adjacent staples,alongside of which they then become wedged. The troublesome staple maybecome free in the first-instance due to loading of a staple stickagainst an unfinished staple stick, or due to breakage of a staple stickduring loading or during violent rapid operation of the staplingmachine. In most cases a loose staple is fed along with the otherswithout difficulty, but in rare instances such a staple may swingupwardly about its bridge to a nearly horizontal position, and thus leadto a staple jam. One primary object of the present invention is toovercome this difficulty and to prevent jams of this character.

The diiiiculty might be overcome by using a very small tolerance orclose fit of the staple magazine about the staples, but this wouldgreatly increase the manufacturing expense. Moreover, the trend indesign is to make these stapling machines out of heavy gauge sheetmetal, but then it is practically impossible to provide a magazinepassage having very small tolerance, as there is always a certain amountof spring or opening up of the material after it leaves the formingdies. There are also irregularities in the thickness of the metal.

Accordingly, an important object of the present invention is toeliminate staple jams, without, however, in any way reducing thetolerance or clearance between the staples and the staple magazine, andwhile making the magazine out of bent heavy gauge sheet metal parts.

To the accomplishment of the foregoing and such other objects as willhereinafter appear,

as hereinafter are more particularly described in the specification andsought to be deflnedin the claims. The specification is accompanied bydrawing, in which:

Fig. 1 is a partially sectioned side elevation of a stapling machineembodying features of my invention Fig. 2 is a partially sectioned sideelevation of a fragment of the magazine, and is explanatory of theinvention;

Fig. 3 is a similar view showing a loose staple being returned to properposition;

Fig. 4 is a similar view of a prior art machine showing a loose stapleturned to nearly horizontal position;

Fig. 5 is a similar view showing how such a staple may lead to a staplejam;

Fig. 6 is an enlarged fragmentary transverse section explanatory of myinvention;

Fig. 7 is a fragmentary section taken in the plane of the line 'l'| ofFig. 6; L

Fig. 8 is a transverse section through a staple magazine loaded with'myimproved staples;

Fig. 9 is a transverse section through a stapling machine and clinchinganvil at the staple driving blade;

Fig. 10 is a simllarsection, but with the anvil moved for temporaryfastening;

Fig. 11 is a view similar to Fig. 10, but showing the temporarilyfastened staple;

Fig. 12 is a section through a machine having a modified drive channel;

Fig. 13 is a similar view illustrating the operation of the modifieddrive channel; and

Fig. 14 is a section explanatory of an advantage of the modified machineand of my improved staple when used as a tacker.

Referring to the drawing, and more particularly to Fig. l, I there showa desk stapling machine of a known type, said machine comprising a baseI2 carrying a clinching anvil l4. A stapling arm generally designated i6is pivotally mounted on base 12. It comprises a staple magazine l8through which staples are fed forwardly by means of a feed spring (notshown) toward a staple driving blade 20, the latter being operated by asuitable plunger 22.

Referring now to Fig. 4 of the drawing, staples 24 are carried on astaple core .26 and are confined thereon by a surrounding staplemagazine wall 28. For any of a number of reasons, the magazine mayoccasionally contain separated staple sticks with a loose staple 3|]therebetween. The diificulty arises principally during faulty orcareless loading of the machine. The operator may drop the staple stickand so break it into a number of pieces, and then, rather than waste thestaples,

attempt to force these pieces one after another into the machine. Inprevalent practice, the machines are of the front-loading type with asafety pawl, such as is indicated at 30 in Fig. 1, and the staples areforced into the front end of the machine against the action of thestaple pusher and staple feed spring. Thus the legs may become turnedand overlapped in condition for a Jam, or may even be jammed during theloading of the staples into the machine. Or the jam may not be noticedduring loading, but may manifest itself when the feed spring attempts topush the staples in the opposite direction, with the turned staplemoving point first.

However, the difllculty is not caused solely by loading, but may ariseduring violent operation of the machine, as in factories using themachine for rapid production purposes. When the the resulting extensionof the feed spring greatly reduces the feed spring pressure, and at thistime the vibration or pounding on the machine may aiford suflicientseparation to permit a staple to rotate. 1 7

On some occasions a loose staple may swing upwardly-over a large angle,as indicated in'Fig. 4. In such case, the ends of the loose staple 33may move alongside of the staples 24 and so bethe limited shown in Fig.7 it is still under control, that'is, it will tend to be moved back tovertical position under pressure of the feed spring, as is illustratedby the successive positions in Figs. 2

' feed pressure will tend than to jam it.

. use of bent heavy gauge sheet metal parts for I20. staples in themachine have been nearly used up,"

come wedged between the staples and the magazine walls. This produces ajam which will prevent further feed of staples, and may prove extremelydifllcult to relieve.

The critical angle, theoretically, is 45. A staple at a less angle willbe restored to normal position. A staple at a greater angle may bejammed.

An ordinary staple comprises legs disposed perpendicularly to aconnecting top or bridge. In accordance with the present invention, thisstaple construction is modified by sloping a leg of the staple. This isindicated at 32 in Fig. 8. The

and 3 of the drawing, instead of tending to Jam, as is illustrated inFigs. 4 and 5. Even if the staple legs were to slightly overrideoneanother, the continued action of the machine will correct the condition,because the staple legs will be disposed collaterally for most of theirlength and the to right the staple rather It will-thus be seen that bysimply sloping the staple leg and by matingly sloping the staplemagazine, jamming of'staples in the magazine may be eifectivelyprevented despite the use of liberal tolerances in the machine, anddespite the the magazine.

The permitted angle of rotation of the staple leg is determined by thelength of the leg relative to the clearance in the magazine, as well asthe angle of the slope of the staple leg. The slope angle used for theleg may, of course, vary great- 1y.- A slight angle has some advantages,but decreases the permissible tolerance in the fit between the magazinepassage and the staples. A large angle increases the tolerance anddecreases the permissible swing of the staple, but may in-" troduce thedisadvantage of reducing the strength of the staple leg against bucklingwhen penetrating thick or hard material. I recommend an angle betweenfive and thirty degrees, with an angle of ten to fifteen degrees asprobably preferable for a satisfactory compromise between the advantagesand disadvantages of more extreme angles.

- Referring now to Fig. 9, I there show a stapling machine having aconventional straight-sided other leg 34 may also be sloped outwardly,but I find it better to leave this leg perpendicular to the bridge 36.The staple magazine of my improved machine is made to fit the sloped legstaple, that is; the wall 38 of the staple core and outside wall 40 ofthe magazine are sloped to mate with the slope of staple leg 32.

' The inner wall of the magazine is thinner and mating with the same.

staple drive channel with a driving blade 52 The permanent clinchinganvil 54 is generally conventional, eizcept that the clinching slot 56is preferably made deeper and curved to more gradually turn the stapleleg 32, than is the case with clinching slot 58 and the perpendicularleg 34. In other words, clinching slot- 58 may be conventional, butclinching slot 56 is modified to compensate for the fact that the leg 32slopes outwardly.

may be fitted to the staples fairly accurately.

' The outer wall is of heavy gauge metal, making an accurate fit verydifficult to obtain. The manufacturer usually aims for a passage fiftyper' cated at 44. Now it will be seen in Fig. 6 that the position 44represents the maximum swing of the staple, for the tip end of thestaple leg has already reached and engaged the magazine wall 40.Moreover, in Fig. 7 it will be seen that this rotation of the staple iswell below 45, and despite the use of a, very liberal tolerance in thestaple magazine. When the staple swings only When it comes to temporaryclinching, the outward slope of the leg 32 constitutes an advantage.Thus, referring to Figs. 10 and 11, I show an anvil having an inwardlydirected clinching slot 60 and an outwardly directed clinching slot 62.It is evident that the initial outward slope of the staple leg 32facilitates the outward clinching of the same in slot 62. In fact, theslot 62 may,

if desired, be made shallower than the slot 60.

This leads to a temporary fastening of the type illustrated in Fig. 11.Some manufacturers prefer a temporary fastening in which the staple legsare both turned outwardly. Such an anvil may, of course, be used in lieuof that .shown in Figs. 10 and 11, and in such case the perpendicula leg34 will be turned outwardly in normal manner, while the sloping leg 32will be turned outwardly even more readily.

Both permanent and temporary clinching slots may be provided on a singleanvil, said anvil being movable in conventional manner to bring eithertype of slot beneath the staple driving blade. One arrangement is shownin Fig. 1, in

which the anvil u is slidable longitudinally or the base in order tobring either of its sets of clinching slots beneath the staple drivingblade.

In Figs. 12 and 13 I illustrate a stapling machine having a modifiedstaple drive channel.

In this channel the wall 64 adjacent the'perpe dicular staple leg 34 isa straight wall, while the wall 66 adjacent the sloping leg 32 is turnedinwardly at 68, thus narrowing the drive channel at to an amountcommensurate with the length of the top or bridge 36 of the staple. Thestaple driving blade 12 is dimensioned to fit between the walls 64 and10, that is, it is no wider than the bridge 36 of the staple. The actionof this machine will be clear from inspection of the drawing. The stapleremains in normal condition until the leg 32 reaches the inwardly slopedwall 68, whereupon the leg 32 is bent or cammed inwardly until itassumes the perpendicular relation shown in broken lines'32'. The actionof the clinching anvil I4 will then be normal.

This arrangement is of advantage not only when the staples are to beclinched, but also, or perhaps even'more importantly, when the staplesare to be used for tacking purposes. In common commercial parlance, a;stapling machine which clinches the staples is called a fastener," whilea machine which merely drives the staple legs into a solid substancesuch as wood, is termed a tacker. Some machines are made with a basewhich can be turned out of. the way, so that the same machine may beused as either a fastener or a tacker. The machine shown in Fig. 1 is ofthis character, and when the base is swung out of the way, the staplemay be driven without any clinching action in order to secure a piece ofpaper.

' cardboardfabrlc or the like 16, to a piece of wood 18. Now when asloping leg staple isused, the

leg is preferably initially straightened t0 Pe 'Pi ndicular relation, asshown at 32' in Fig. 13, before driving the same into the wood 18. Afterthe staple has been driven, the leg 32 tends to swin outwardly, becauseof its own resilience, and thi helps bind the staple against accidentalremoval.

While I have illustrated permanent clinching slots in Figs. 12 and 13,it will be understood that the special driving channel there shown mayalso be used with temporary clinching slots, although the special drivechannel is obviously of greater advantage for permanent clinching andfor tacking, rather than for temporary clinching. However, in all ofthese cases there is some advantage in bringing the legs to parallelcondition at the instant of driving the same, when the material to bestapled is of great thickness or unusual hardness or difficult topenetrate.

Both staple legs may be sloped, but inasmuch as the object of preventingjamming of the staple will be fulfllled while sloping a single leg, itis preferred to slope only one leg. The sloping staple leg may be slopedinwardly instead of outwardly to fulfill the desired object ofpreventing rotation of the staple about the bridge. of course, if thesloping leg is to be cammedto perpendicular position at the instant ofdriving the same, the outwardly sloping leg is preferable to theinwardly sloping leg, because the means for camming the leg toperpendicular position is very simple, as was described in connectionwith Figs. 12 and 13. With an inwardly sloping leg the camming meanswould have to be automatically retracted as the staple driver descends.

It is believed that the construction and operation of my improved stapleand stapling machine for use with the same, as well as the importantadvantages thereof, will be apparent from the foregoing detaileddescription thereof. It will also be apparent that while I have shownand described my invention in several preferred forms, other changes andmodifications may be made in the structures disclosed, without deto bedefined in the following claims.

I claim:

1. A staple for use in a magazine type stapling.

machine of ordinary character except that the staple guide passage ofthe magazine slopes ,to

receive a matingly sloping staple leg, said staple being formed of aslender, uniform, readily deformable wire, and having 3:. bridge withtwo legs depending therefrom, one of said legs being perpendicular tothe bridge. and the other sloping at an angle of from five to iihirtydegrees from perpendicular.

2. A staple for use in a magazine type stapling machine of ordinarycharacter except that the staple guide passage of the magazine slopes toreceive a matingly sloping staple leg, said staple being formed of auniform wire, and having a bridge with two legs depending therefrom, oneof said legs being perpendicular to the bridge,

and the other sloping outwardly.

3. A staple for use in a magazine type stapling machine of ordinarycharacter except that the staple guide passage of the magazine slopes toreceive a matingly sloping staple leg, said staple being formed of aslender, uniform, readily deformable wire, and having a bridge with twolegs depending therefrom, one of said legs being perpendicular to thebridge, and the other sloping outwardly at.an angle of from five tothirty degrees from perpendicular.

4. A staple for use in a magazine type stapling machine of ordinarycharacter except that the staple guide passage of the magazine slopes toreceive a matingly sloping staple leg, said staple being formed of aslender, uniform, readily deto the bridge. LOU oss'rr'mn.

